Interlocked architectures based on a bis-calix[4]pyrrole macrocycle for ion-pair recognition

Identifier:  TDX:2524

Handle: https://hdl.handle.net/20.500.11797/TDX2524

Authors:  Romero Lopez, Jose Ramon

Abstract:
This doctoral thesis deals with the synthesis of mechanically interlocked molecules featuring a rotaxane topology. We report the synthesis of a [2]rotaxane based on a bis-calix[4]pyrrole macrocycle and a 3,5-bis-amidepyridil-N-oxide axle in a remarkable 50% yield through an optimized “in situ” capping strategy using copper(I)-catalysed azide-alkyne cycloaddition reaction. During the optimization studies we concluded that the use of anion templation was detrimental not only for the isolation of the pure [2]rotaxane but also for the good performance of the catalytic reaction. We determined the thermodynamic parameters of the binding process of the [2]rotaxane with different tetraalkylammonium ion-pairs in two different solvents (i.e. chloroform and acetone) and we could identify different binding geometries in the binding process (1:1 and 2:1 complexes). We have also studied the influence of the stopper size in the synthesis of the interlocked structure. We concluded that the use of smaller stoppers mainly leads to the recovery of non-interlocked components from the reaction mixture: free macrocycle and linear component. Moreover, we could identify traces of a new species that we attributed to a hypothetical [3]rotaxane structure after a complete set of characterization analysis. The studies carried out in this doctoral thesis provided deeper knowledge on the synthesis of interlocked structures. Moreover, they can be considered and important first step towards the application of this kind of structures as molecular machines.